Agar is obtained from
A. Red algae
B. Brown algae
C. Blue-green algae
D. Green algae.

Hint: Agar is known as the vegetarian gelatin due to its origin. It comprises a jelly-like structure. It can be white or semi-transparent. It has great use in both the food industry for making desserts, jelly, etc and microbiological experiments as the culture medium. It is mainly composed of polysaccharides.

Complete answer: Algae are either unicellular or multicellular eukaryotic organisms. These are capable of synthesizing their food by photosynthesis. There are major three types of algae that are found in the environment. These are red algae, brown algae, and green algae.
Red algae: The other name of red algae is Rhodophyta. These are found in both freshwater and marine water. Red algae comprise a pigment known as phycocyanin that causes the red color of the organism. The cell wall of the red algae comprises two polysaccharides named agarose and agaropectin. From these two polysaccharides, agar-agar is extracted.
Brown algae: these algae are mainly marine organisms. The organism comprises a pigment called fucoxanthin that is responsible for the brown color of the algae.
Green algae: This type of algae possesses chlorophyll pigment. That’s why it is called green algae. Due to the presence of chlorophyll, it can do photosynthesis to produce food.
Blue-green algae: Blue-green algae is also known as cyanobacteria. These are not large. It is a prokaryotic organism that can perform photosynthesis due to the presence of thylakoids. These are a toxic organism that produces a toxin called cyanotoxins.
So, the correct answer is “Option A”.

Note: Algae are free-living organisms. It can be found in moist aquatic places. Both sexual and asexual reproduction is found in algae. Asexual reproduction involves the formation of spores. Sexual reproduction includes the mating of haploid gametes. It acts as the primary good source of many organisms.